Presenter:

Sally Tracy(Princeton University)

Authors:

Sally Tracy(Princeton University)

Stefan Turneaure(Washington State Univeristy)

Thomas Duffy(Princeton University)

SiO2 and TiO2 are known to undergo phase transitions under shock compression. The nature of these transitions and the resulting high-pressure phases are of fundamental interest for understanding the dynamic response of minerals, for characterizing natural impact sites, and for understanding high-pressure phases of planetary interiors. In this study, in situ x-ray diffraction experiments on shock-compressed SiO2 and TiO2 were conducted at the Dynamic Compression Sector of the Advanced Photon Source. The lattice-level structure was investigated through time-resolved x-ray diffraction measurements on samples reaching a peak stress ranging from 12 to 70 GPa. For SiO2, we have examined natural low-porosity polycrystals as well as fused silica. For TiO2, we have studied single crystals in different orientations. Our results provide direct constraints on the nature of the high-pressure phases formed under shock compression in these materials.